The present invention relates to a magnetic head supporting device for supporting a head which is used to record on or reproduce information from both sides of a flexible recording medium, such as a floppy disk.
In general, magnetic head supporting devices comprise a pair of head arms extending parallel to each other, and a pair of magnetic heads mounted individually on the distal end portions of the arms and facing each other. In read/write operation, a recording medium is held between the magnetic heads from both sides. For an accurate operation, the magnetic heads must be securely in contact with the medium. To attain this, the heads are pressed against the recording medium with a predetermined load.
Conventionally known are supporting devices which use gimbal springs or a combination of gimbal springs and leaf springs, as means for applying the predetermined load to the magnetic heads.
In a supporting device of the former type, a gimbal spring is attached to each of the head arms, and a magnetic head is fixed in the center of each gimbal spring. In operation, when the magnetic heads hold a recording medium between them, the gimbal springs are deformed or distorted so as to move away from the medium. An urging force, produced in the gimbal springs by such deformation, is applied as a load, to the magnetic heads. The gimbal springs, which allow the magnetic heads to move around both the x- and y-axes, serve to absorb dimensional errors of the device and distortion of the recording medium.
In the supporting device constructed in this manner, the gimbal springs apply the predetermined load to the magnetic heads by being deformed. In order to stand such deformation and to produce the load, the springs must have a relatively large spring force and high rigidity. If the gimbal springs have a larger spring force and higher rigidity, however, the degree of freedom of their deformation lowers in proportion. Moreover, the degree of freedom is less in a deformed state than in an undeformed or neutral state. Thus, in the arrangement described above, the degree of freedom of the deformation of the gimbal springs, or of the movement of the magnetic heads, is so low that it is often unable to compensate for irregularities in the recording medium and dimensional errors of the supporting device.
In a supporting device of the latter type, on the other hand, a magnetic head is fixed to a gimbal spring, which cantilevers from the distal end of each of a pair of head arms. Likewise, a leaf spring cantilevers from the distal end of the head arm, and a pivot pin, which is fixed to the free end of the leaf spring, is in contact with the gimbal spring. Thus, the gimbal spring and the magnetic head are urged toward the recording medium by the leaf spring.
According to the supporting device constructed in this manner, a load is applied to the magnetic head by means of the leaf spring, so that the gimbal spring need not be deformed. In such an arrangement, the gimbal spring can fully perform its functions. However, this conventional device is subject to the following drawback. In general, when the device is in an unloaded state, the head arms are moved away from each other in order to separate the magnetic heads from the recording medium. In this supporting device, however, the gimbal springs, which are urged toward the recording medium by the leaf springs, bend toward the medium as the head arms move. In order to separate the magnetic heads securely from the recording medium, therefore, the head arms must be moved a significant distance. Thus, the supporting device of this type requires a wide mounting space when it is set in a disk drive device or the like.